Never Plaster Over Distemper!!
13 Years ago I went on a short plastering course that would set me up with a skill that most would avoid like the plague. People would much rather pay through the nose than get involved in this alien like trade that gives the lucky few the ability to make something stick to a wall and eventually look completely flat and shiny..so when I finished my course I was very proud and went about doing a few little jobs around the house that I new would be within my skill set and not too tricky. These involved small jobs that would give me confidence as I went on so that eventually I'd be able to go about skimming a whole room, or a ceiling and ultimately entire houses. No mountain high enough for my aspirations to be a successful plasterer.
A good friend of mine new I'd been on a course and so in his helpful and kind way he arranged for me to meet a friend of his to do some plastering for him..wow..my first job. I couldn't wait, so I packed up all my tools and trowels and stuffed them as neatly as I could in to my classic 1970 VW Beetle, ready for its very first trip as a tradesman van!!.
I arrived at the job introducing myself as I proudly unleashed my trowels and buckets into the offending room that required my skills as a newly qualified plasterer. There is nothing worse than what I encountered in that room. I did absolutely nothing wrong with regard to how I prepared the ceiling before I plastered it, nor, did I skip any of the very important stages of plastering that I knew were completely essential in assuring a good quality finish. There is absolutely nothing that prepares you for what happened after I had finished a 2 hour set of skimming the ceiling...the whole damn lot fell on my head. No word of a lie, as I pulled my trowel over the plaster for the last time, the middle of the ceiling collapsed inwards and on to my head...and the floor... and in to my buckets.... and all over my tools, followed by the rest of the ceiling, leaving perhaps a few inches around the edge..Great!!.... was not the word I used to describe my upset and displeasure as to the circumstances I now found myself in. When this happens its not just the ceiling that collapses.. its your entire world.. I'm now stood in the middle of a room, on my stilts, hawk and trowel in hand and 2 hours work all over my head and the floor. I need this to not happen to anyone else hence if you read this you will learn from my mistake.
Always know your tools, your materials and more importantly the surface you put your materials on. In this instance I used my tools to put my materials on to a surface that at some point in the past had been painted in a substance I would liken to the devils paint. Also known as "distemper." I certainly had a temper!! But I didn't now what distemper was. I've come across it 2 times since and both times followed a very strict method of ensuring my mishap would never be repeated.
Distemper is a chalk based paint used in the past to really upset people in the future. As it is chalk based nothing sticks to it, so for instance if you wanted to paint over it you wouldn't be able to or similarly if you wanted to skim over it. An even bigger no,no!! I think you get the picture. Below is my recipe for evading this disaster zone. I cover every aspect of firstly, how to remove the chalky, white, flaky, powdery material and secondly how to ensure you prepare the surface to ensure your plaster bonds correctly.
This picture shows the first indication that a paint is not playing ball. The paint is flaky and comes away from the surface very easily. Also if you PVA over the top or apply warm water you may see bubbles appear where it has softened the material and it comes away from the wall or ceiling. If you were to get a wet sponge and rub the surface the white paint easily transfers from the wall to the sponge. Most importantly it feels chalky to the touch.
Tackle the surface in stages. Use warm/hot water to soften the paint. I use a paint roller to cover bigger areas faster but this can be very messy so I would advise a large sponge. Alternatively you could use a paper steamer however be careful not to damage old plaster with too much steam if you are only planning on a skim. Give it a couple of seconds to soften and then use a decorators scraper to lift the paint away from the surface. It should come away very easily proving to you that had you skimmed over the top, it wouldn't have been long before it fell on your head!!
Move across the ceiling until you have completely removed the white surface level of paint. You can see that there is still a white residue being left behind. This is still chalky and you still cannot PVA over it to skim as it will not take to it. Wearing a dust mask is essential as old paint is not to be ingested. Old artex can contain asbestos and some paints used to contain lead. Both are harmful. If you are unsure about the artex you should contact an asbestos specialist who will confirm if this should be removed. If asbestos is present you should definitely not continue with this process and you should hand over to the specialist.
You are now going to need these items.
A bucket of warm water with a solution of sugar soap, a sponge and some gloves.....
.....time to wash the ceiling. All or as much as possible of the white residue left behind from the paint needs to be removed.
The next picture shows the ceiling semi washed. You can see the residue being removed as it begins to appear less white. Luckily I can see the residue being removed as the background colour is not white, however, if the background is also white you will have to keep checking your sponge to see that the residue is gone.
The sugar soap will help to remove the chalk residue. Once you have done this you need to stabilise the ceiling. You can buy a stabilising solution from most builders merchants.
This is the one I bought below.
You can either paint this on or roll it on. It dries quickly and it completely stabilises the chalk. You can see the surface in the next image is now shiny and it will accept a layer of PVA. Mix the PVA 50/50 with water and apply thinly. Do this because, now the surface has been stabilised it is essentially water proofed. The solution has created a barrier therefore the PVA will hang around longer than normal as there will be no suction from the wall/ceiling. Be patient. If you apply too much and its mixed too thinly the PVA will run down the wall. Allow the first coat of PVA to completely dry and then you are ready to skim. As normal, prior to skimming apply another coat of PVA and allow to go tacky before you start skimming.
The image below shows the ceiling after my first coat of PVA. You can see how wet and runny it is!! It hang around for ages so I opened windows upstairs and downstairs to create a flow of air through the house. This will help the PVA dry quicker.
Ceiling gets skimmed when the PVA is tacky, not when it's dry and not whilst its still runny and wet. To learn how to skim a wall you can go to the Home page and watch the video tutorial How to Skim a Wall from Start to Finish. Please subscribe to my channel for further tutorials.
Ceiling is finished and is drying.
The finished article.